How to create a glow animated circle that surrounds a sphere
use object vertex positions to make a ring (math node set to absolute makes it a ring for example if you choose z value from vertex position every vertex with value more than 1 is white and with absolute node -1 and less values also means white and you can move positions before that ,so ring moves along z axes this(the marked value) is also what you can keyframe to animate ring movement ) then use the ring as a texture and map node to rotate it and use it as a factor to mix diffuse and emission shaders and also use some another axes like x to change ring color based on it.

there are some options to make glowing effect but this is an easy way, first check emission

in compositing blur emission part and mix it with rendered image